"This data is suggesting that both patients who are obese who are metabolically unhealthy and patients who are obese who are metabolically healthy are both at increased risk of death from cardiovascular disease, such that benign obesity may indeed be a myth."

Heart risk

The British Heart Foundation says obesity is a known risk factor for heart disease and the research shows there is no healthy level of obesity.

She said it was useful to think of lifestyle overall rather than individual risk factors.

"As well as watching your weight, if you stop smoking, get regular physical activity and keep your blood pressure and cholesterol levels at a healthy level, you can make a real difference in reducing your risk of heart disease.

"If you are concerned about your weight and want to know more about the changes you should make, visit your GP to talk it through."